# Finding unit vectors

• Feb 6th 2008, 03:15 PM
overduex
Finding unit vectors

Directions: Find a unit vector in the direction of line PQ.
P(7, -4) Q(-3, 2)

the textbook say the answer is: 1/SquareRoot(34) * (-5, 3)
sorry I don't know how to make the square root symbol...

ok, so I know how to find unit vectors for single points. can anyone please explain how to do this one? is it similar to the other method?

Thanks!
• Feb 6th 2008, 03:29 PM
bobak
find the vector PQ first which is (-10 , 6) , then divide by the magnitude of the vector to get a unit vector.
• Feb 6th 2008, 03:44 PM
overduex
Quote:

Originally Posted by bobak
find the vector PQ first which is (-10 , 6) , then divide by the magnitude of the vector to get a unit vector.

This might be a stupid question, but how did you get (-10, 6) ??
• Feb 6th 2008, 03:57 PM
Plato
To find a unit vector in any direction, one divides by the length in that direction.
If V is a non-zero vector then $\frac{1}{{\left\| V \right\|}}
$
is a unit vector parallel to V.